Mozart would be a fine place to begin. His music is predominantly diatonic, yet he often uses chromatic apoggiatura's, passing notes etc.
Yet even this wouldnt class his music as chromatic, as the intervals are still mostly diatonic. When I talk about melodic chromaticism, Im thinking the stuff that began to appear during the romantic era. Stuff like Rimski Korsakov's 'Flight of the Bumblebee', Chopin's Etude Op10 No2 etc.
I think this style is really interesting, as it focuses much more on the 'contour' of the melodic line, rather then with the individual intervals. Iv composed a little phrase to show you the kind of thing I mean. The harmony is fairly chromatic but the melody even more so:
http://download.yousendit.com/7A13CA226247628C
This style of music is very applicable to kid's cartoon I think. The semiquaver chromatic melodies always make me think of little ants scurrying along!
Id be interested to hear what you guys think of this style, and more importantly, how you could apply it to your music.
For instance, I often thought you could make some wicked metal guitar solo's with this kind of thing. Makes me want to get my Ibanez and fish out my Satrina technique book, lol. Well, almost...
TB